Production of starch edible films using chitin nanocrystals extracted from mushroom

Abstract

This study aimed to produce chitin nanocrystals (CHNC) from mushroom and investigate their potential application in improving physicochemical properties of starch edible films. Alpha-Chitin was extracted by demineralisation, deproteination, and discoloration treatments of mushroom powder, while CHNC were obtained by acid hydrolysis. Hydrolysis using hydrochloric acid for 120 min at concentration of 3 m was selected as the best conditions for CHNC. X-ray Diffraction Analysis and Transmission Electron Microscopy showed a crystallinity index of 77 ± 1.2% and needle-like morphology for CHNC with an average length of 81 nm and diameter of 19 nm. Chemical, morphological, and thermal properties of CHNC were characterised using FTIR, SEM, and DSC analysis and results indicated an increase of the purity of CHNC after hydrolysis. Different concentrations of CHNC (1, 3, 5, and 7% W/W) were used to produce a nanocomposite green film from corn starch. Quantification of the mechanical properties of the green films documented a direct relationship between CHNC concentration and the samples tensile strength and Young's modulus. However, increasing CHNC concentration resulted in a reduction in the samples' water vapour permeability, water solubility, and moisture absorption. The results of this study are promising, suggesting enhancements in the physicochemical properties of the edible film through CHNC incorporation.